Radiation therapy utilizes several types of ionizing radiation, such as beta-rays, gamma rays and x-rays, as well as high-energy protons and neutrons applied to malignant tissue to prevent and control the spread of cancer. While ionizing radiation is capable of destroying cancerous tissue, it is also capable of damaging healthy tissue inadvertently exposed thereto. Thus, a necessary precondition for treatment is the safeguard of patients and personnel from accidental radiation exposure.
Various methods of shielding radiation in rooms and walls are known and in use in hospitals around the world. However, most of these methods are expensive to manufacture and can be complicated to use. Many use complex “radiation mazes” composed of thick leaded walls with multiple 90-degree turns, capped off with a heavy leaded door, often weighing thousands of pounds. Typically, the many walls are composed of thick concrete or other materials known for their ability to absorb or block ionizing radiation. These methods have several drawbacks. The heavy doors require mechanized assistance through automated motors and the like. This is both time consuming and dangerous, as technicians and patients alike can get caught in the door if they are not careful. Furthermore, it is time consuming for a therapist whenever the patient requires adjustment or assistance. Moreover, the closing of a thick lead door has a negative psychological impact on the patient who can feel entombed in the therapy room. Additionally, such a room is expensive and the required footprint is very large, resulting in a lot of unusable space. Finally, it has been known for these heavy doors to become stuck in the closed position due to motor or hinge failure. The patient is then alone in the treatment room and must wait for the heavy door to be opened by some other means.
Some radiation therapy rooms have been created with a doorless entry system. See, Dawson et al., “Doorless Entry System,” Medical Physics, fol. 25, No. 2 (Feb. 1998), the entire disclosure and subject matter of which is hereby incorporated herein by reference. While such a system meets some of the above identified challenges, it is desired to increase the radiation attenuation, by improving the system geometry.